The present invention relates to an internal combustion engine with exhaust gas pipe for taking exhaust gases from the engine's combustion chamber and an intake pipe for supplying air to the said combustion chamber, and a turbo charging system with a high-pressure turbine that interacts with a high-pressure compressor and a low-pressure turbine that interacts with a low-pressure compressor, for recovery of energy from the engine's exhaust gas flow and pressurizing of the engine's intake air, which high-pressure turbine is connected to the low-pressure turbine via a duct.
Diesel engines for heavy vehicles normally require a considerable amount of space as they have various systems for supercharging, cooling and exhaust gas after-treatment. For example, there are turbo-charging systems with two-stage supercharging that are usually based on standard units designed for single-stage charging.
An exhaust gas pressure regulator is used in many types of engine to create a back pressure in the exhaust gas system—, for example in order to improve the braking force of a four-stroke internal combustion engine. In addition, the back pressure from an exhaust gas pressure regulator can be utilized to increase the amount of re-circulated gas to the intake side, so-called EGR-gas. In addition, the back pressure can be utilized for heating up the engine more quickly when starting. An exhaust gas pressure regulator is normally located downstream of turbo charging systems in order not to have an adverse effect on the efficiency.
It is desirable to achieve an internal combustion engine with two-stage turbo charging system and exhaust gas pressure regulator that does not make significant demands in respect of space and weight.
An internal combustion engine designed according to an aspect of the invention comprises an exhaust gas pipe for taking exhaust gases from the engine's combustion chamber and an intake pipe for supplying air to the said combustion chamber, a turbo charging system with a high-pressure turbine that interacts with a high-pressure compressor and a low-pressure turbine that interacts with a low-pressure compressor, for recovery of energy from the engine's exhaust gas flow and pressurizing of the engine's intake air, which high-pressure turbine is connected to the low-pressure turbine via a duct, and is characterized according to the invention in that an exhaust gas pressure regulator is placed in the duct between the high-pressure turbine and the low-pressure turbine. As a result of the position of the exhaust gas pressure regulator according to the invention, an existing component in the turbo charging system can be utilized for exhaust gas pressure regulation, which results in a saving in space and weight.
Advantageous embodiments of the invention are apparent from the following description.